Amputation of limbs or digits can occur due to trauma or because of surgical removal. Examples of trauma include loss of fingers in machinery accidents, loss of limbs in car accidents or as a result of land mine explosions. Surgical removal can also be indicated as a result of cardio-vascular disease, diabetes and cancerous tumours to the bone or soft tissues.
After amputation, it is common to fit an external endo-prosthetic device that is attached to the body via by a skin interface. This commonly involves the manufacture of a custom-made socket which is secured to the stump using straps or clamps. A number of disadvantages arise from the use of such endo-prosthetic devices. For example:
(1) Skin is not a satisfactory high load bearing structure and often breaks down under load, becoming inflamed and uncomfortable and, in severe cases, pressure sores are formed which are difficult to heal.
(2) Changes in the shape of the stump may mean that a new custom-made socket is required.
(3) The use of sockets for receiving the stump are commonly sweaty and uncomfortable.
(4) Where a joint is involved, the external prosthesis is usually moved by muscle groups situated at a distance from the attached prosthesis and therefore motion is inefficient and unnatural.